It is well known in vehicle seat belts to provide a passive seat belt system in which the outboard end of the seat belt is mounted on the vehicle door by a door mounted retractor so that the retractor winds the belt about the occupant when the door is closed. Opening movement of the door unwinds the belt and carries the belt outwardly and forwardly with respect to the seated occupant to permit ingress and egress. The door mounted retractor has an inertia locking mechanism associated therewith to lock the reel against belt unwinding rotation in response to a sensed acceleration condition. Such an inertia locking mechanism typically includes a lock bar which rests upon an inertia mass with the inertia mass becoming excited by the acceleration condition and moving the lock bar into engagement with ratchet teeth carried on the reel.
When an occupant closes the door, the door and the retractor are rapidly decelerated as the door reaches the closed position. This deceleration induces an intermittent locking of the inertia locking mechanism. A weatherstrip interposed between the door opening and the door is compressed during such deceleration of the door to effectively cushion and quiet the closure of the door. The compression of the weatherstrip coupled with any other compliance built into the door, permits the retractor to travel somewhat inwardly beyond its normal door closed position. Then, the weatherstrip compression pushes the door outwardly to its normal closed position established by the door latch.
The present invention provides a brake adapted to retard the windup of the belt on the reel so that the belt is not overwound during the door overtravel permitted by compression of the weatherstrip so that the belt is not locked in its overwound condition during the intermittent actuation of the reel locking mechanism as the door reaches the fully closed position.